The following Patent Document 1 discloses a pneumatic valve for a rocket engine used in space development. In such a pneumatic valve, typically, the flow of a fluid (for example, a propellant) that flows in from an inlet pipe is controlled by opening and closing of a poppet that is a valve body.
In a closed state, the poppet is sealed by being pressed against a seat surface with a specified axial force by a spring built into a valve casing, and thereby leakage of the fluid to a downstream side is prevented. On the other hand, in an open state, an actuating gas is supplied to a pressure chamber within the valve casing with a specified pressure, and a diaphragm is pushed up, and thereby, the poppet is separated from the seat surface and the fluid flows to the downstream side.